The microbiological quality of paper products is critical for producers of liquid board and food packaging grade material which must meet mandated standards. Producers of other paper grades such as tissue or cupstock often adhere to these standards as well. The current standard for food packaging grade material in the United States is 250 spores/gram of paper. This is determined by the Dairyman's method, a plate count enumeration technique which requires a 48 hour incubation period. A more rapid diagnosis of a contamination problem would result in significantly less wasted product and an overall increase in mill productivity.
Paper production provides many favorable niches for the proliferation of a range of microorganisms. Among the most costly and persistent problems is control of spore forming bacteria (SFB). Unlike most bacteria, SFB can pass through the dryer sections of production to pose a contamination threat when that product is used in food packaging. Spores are resistant to all but the most toxic of biocides. These compounds pose health and safety concerns within the mill and environmental concerns outside the mill. Many Bacillus and Paenbacillus strains produce food spoilage related enzymes such as caseinase and amylase. A number of industry trends are generating more concern over the microbiological quality of paper used for food packaging. Recycled fiber which often contains starch and coating material can support microbial growth. As the fraction of recycled material going into production increases, so will the chance for contamination of the finished product. Coinciding with this increase in recycled fiber is pressure to decrease the use of biocides for control of microbial growth. Fast, reliable, simple and cost effective monitoring of product quality will increase overall production efficiency by allowing problematic populations to be controlled while at the same time permitting biocides to be applied when needed.